Cobwebby Thistle
Cirsium occidentale
- Native to:
- Mexico, United States
iNaturalist: © sadie_hickey (iNaturalist #126018929)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Cirsium
- Species:
- Cirsium occidentale
- USDA Symbol:
- CIOC
Growth Characteristics
- Life Cycle:
- Biennial | Perennial
- Growth Habit:
- Forb/herb
- Height:
- 200 cm
- Light Requirements:
- Full Sun,Part Shade
- Drought Tolerance:
- High
- Bloom Months:
- apr,may,jun,jul
- Bloom Colors:
- red, magenta, pink, white
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
- Hummingbirds:
- ★☆☆☆☆ Documented hummingbird visits (GBIF)
Keystone Species Ranking
- Pollen Specialist Bee Keystone:
- ★★★★☆ Native pollen specialist bee species supported by this genus (NWF)
Host Plant for Caterpillars
figwort stem borer moth (Papaipema sauzalitae), Mylitta crescent (Phyciodes mylitta)
Reported Fauna Sightings
Bees: Anthophora urbana, Bombus californicus, van Dyke (Bombus vandykei), Yellow bumble bee (Bombus fervidus), Yellow-faced bumble (Bombus vosnesenskii) Hummingbirds: Anna's Hummingbird (Calypte anna) Moths:Hemaris thetis Butterflies:Anise Swallowtail (Papilio zelicaon), Painted Lady (Vanessa cardui), Pale Swallowtail (Papilio eurymedon), Western Tiger Swallowtail (Papilio rutulus)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, hummingbirds, birds
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts from rootstock following fire; often increases in abundance in post-fire environments.
Soil Requirements
- Soil Type:
- sandy, well-drained, nutrient-poor soil
- pH:
- 6.0 - 8.0 (slightly acidic to slightly alkaline)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- Prefers open, sunny locations in native range
Propagation & Germination
- Stratification:
- None required
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate readily without pretreatment. Surface sow as seeds may need light.
The above propagation data sourced from Claude AI
Pre-treatment: None required
Source: npn.rngr.net